Should we be using `ModelList` in our models? I found it was the only way to detect changes in a lis...

# compose

[Ian Warwick]

Should we be using ModelList in our models? I found it was the only way to detect changes in a list but not sure if its for use in @Model annotated classes 🤔

[Adam Powell]

If you want to detect changes in the content of a mutable list, yes, that's what ModelList is for. Alternatively if you're using immutable lists and mutating a reference to said immutable list in a @Model class, that will also do what you're after

[Adam Powell]

@Model observation is shallow, it will only make changes to the class annotated with it observable. If you change a plain old mutable object that happens to be held in a val in an @Model class, that change won't be tracked.

[Adam Powell]

But it's perfectly fine for @Model objects to reference one another

[Ian Warwick]

Thankyou @Adam Powell! I guess I was confused because it was in the .frames package and that seemed a bit low level package for end user 🙂

[Ian Warwick]

If you want to detect changes in the content of a mutable list, yes, that's what ModelList is for. Alternatively if you're using immutable lists and mutating a reference to said immutable list in a @Model class, that will also do what you're after

Cool, can that reference be a MutableList or must it be a ModelList when mutating the ref?

[Adam Powell]

We're thinking about naming for all of this stuff. The word, "snapshot" keeps coming back up. "Model" is uncomfortably generic and, "frames" describes the mechanism but not really the usage, and when it appears so close to UI code it's hard not to think FrameLayout on some level

[Adam Powell]

The reference can be whatever you want, but if you change a mutable object that isn't itself @Model, compose won't know about it unless you tell it explicitly

[Ian Warwick]

cool 👍

[Adam Powell]

And using anything other than @Model (or immutable objects) is going to get very complicated in the presence of some of our multithreading ambitions

[Ian Warwick]

nice I am happy with @Model its working super nice! :)